Helicobacter pylori gastritis in cats with long-term natural infection as a model of human disease

A natural infection with Helicobacter pylori (H. pylori) in domestic cats ( Felis cattus) less than 2 years of age has been well described in a closed colony of animals, Six cats from this colony that were serially evaluated b y culture, polymerase chain reaction, and light and electron microscopy for a period of 3 years demonstrated persistent gastric colonization with a si ngle cag(-) vac(+) strain of H, pylori. In these cats, as well as five othe r 5- to 6-year-old cats that were examined, a long-term infection resulted in chronic diffuse lymphofollicular atrophic gastritis with areas of mucosa l dysplasia in the antrum and predominantly midsuperficial gastritis in the body and cardia, Topographically, the distribution of lesions was similar in both young and older cats and closely resembled that found in humans, wi th the most severe changes occurring in the gastric antrum. Few granulocyte s and no significant elevation in mast cells were seen in older H, pylori-i nfected cats compared with uninfected controls; however, marked increases i n interepithelial globule leukocytes and numerous active mucosal lymphoid f ollicles were present in infected animals, Indices of gastritis were signif icantly greater in older infected cats when compared with uninfected contro ls and younger cats (P < 0.05). The antral cell proliferation index of infe cted older cats was significantly (P = 0.021) greater than that of uninfect ed controls, Apoptotic indices of the gastric antrum and body of infected c ats were significantly (P = 0.01) increased versus controls. Chronic infect ion with H, pylori in cats shares many features of long-term H, pylori infe ction in humans, including the development of preneoplastic processes. This similarity provides useful, comparative insights into host-pathogen intera ctions.